Childhood lymphoma

What is lymphoma?

Lymphoma affects the lymphatic system. This consists of thin tubes called lymph vessels that run throughout the body and carry lymph, a colourless, watery fluid that contains white blood cells called lymphocytes.

Dotted along the lymph vessels are groups of small, bean-shaped lumps called lymph nodes or glands. Clusters of lymph nodes are found under the arms, around the neck and under the chin, and throughout the pelvis, groin, abdomen and chest. They make and store infection-fighting cells, especially lymphocytes.

Lymphoma results when a lymphocyte undergoes a malignant change and multiplies, eventually crowding out healthy cells and creating tumours. These tumours enlarge the lymph nodes and/or grow in other sites that are part of the immune system.

Lymphoma accounts for one in 10 childhood cancers and is the third most common cancer in childhood. Lymphomas are divided into Hodgkin lymphoma and non-Hodgkin lymphoma. Non-Hodgkin is more common in young children, and Hodgkin lymphoma is more common in adolescents. Lymphoma is twice as common in boys than girls.

Lymphoma symptoms

There may be no symptoms until the lymphoma has spread. Lymphoma can start in almost any part of the lymphatic system and spread to almost any other part of the body, including the liver, bone marrow (the spongy tissue inside the large bones of the body that makes blood cells) and the spleen (an organ in the upper abdomen that makes lymphocytes and filters old blood cells from the blood).

Hodgkin lymphoma usually presents with painless swelling of the lymph nodes (lymphadenopathy), most frequently in the neck. Often people get a similar swelling (lymphadenopathy) if they have a simple cold. However, in Hodgkin lymphoma the swelling is much larger and firmer.

Other symptoms (called B symptoms) are:

• Fever for which no cause can be found
• Fatigue or extreme tiredness
• Paleness
• Night sweats (usually a sign of Hodgkin)
• Weight loss

Often lymphomas have spread all over the body before the person is aware they have a problem.

Lymphoma causes

The exact cause of lymphoma is uncertain. Scientists have looked at many things that may be linked with lymphomas. They have found many connections and risk factors but are unable to say exactly what the causes are.

Exposure to certain viruses and bacteria is associated with lymphoma. For example, Epstein-Barr virus may increase the risk of getting lymphoma and people who are HIV positive have an increased risk of lymphoma.

Genetic and environmental factors, such as exposure to pesticides, have also been implicated.

Lymphoma treatments

The two main types of lymphoma involve different types of white blood cell and it's important to get the exact diagnosis - determined mainly by what the cells look like under the microscope.

Each type of lymphoma needs slightly different treatments and has different prognoses or cure rates. Doctors will also stage the tumour - this means working out how far it has spread around the body.

As recently as 1950, lymphoma was almost inevitably fatal, but these days more than 90 per cent of those newly diagnosed with Hodgkin lymphoma can expect to be cured. Non-Hodgkin lymphoma is less easily treated, with an overall cure rate of about 75 per cent.

Lymphoma is usually treated by a combination of chemotherapy, radiotherapy, surgery and/or bone marrow transplants. The main treatment is chemotherapy, in which drugs are used to kill cancer cells and shrink tumours.

Radiotherapy involves the use of high-energy x-rays to kill the cancer cells. Bone marrow transplantation is a newer type of treatment, which allows very high doses of anti-cancer drugs to be given.

Many children with lymphoma will be offered the chance to be treated as part of a clinical trial. While they or their family may be frightened by the idea that they're being used as some sort of guinea pig, they'll be very carefully monitored by doctors during the trial. Trials are the only way to find better treatments.

Advice and support

Lymphoma Association

• Helpline: 0808 808 5555
• Email: information@lymphoma.org.uk
• Website: www.lymphoma.org.uk